The management of numbers is an important task in the operation of communications networks. It includes managing the assignment of subscriber stations to call numbers, i.e. managing the addressing of subscriber terminals in communications networks.
The article "System 12, Operation and Maintenance" by E. Bertoli et al., Electrical Communications Volume 56, number 23, 1981, pages 184 to 197 describes the realization of a directory number administration for a part of a telephone network. The invention starts with this realization of a directory number administration.
The assignment of call numbers to the subscriber stations of one or several exchanges is controlled by a central operation and maintenance system. This assignment is changed by blocking and releasing subscriber station lines and by changing the routing guidance tables of the exchanges. The implementation of such a change is brought about by personnel of the operation and maintenance center with the input of a corresponding change order.
The execution of such changes is a management task for the network operator and involves high safety requirements. For that reason such a change order can only be entered by predetermined personnel of the operation and maintenance center and the personnel must be identified with passwords.
Problems occur with this type of changes in the assignment of call numbers if installers must perform local work in the respective subscriber station before the change is made.
This is particularly the case in a deregulated subscriber station area in which the subscriber networks of two or more network operators share the subscriber station area and thereby also the numbering range of the subscriber area. If a subscriber changes from one network operator to another, an installer must reconnect the subscriber's terminal from one station in the subscriber network of one network operator to a station of the other network operator. The subscriber cannot be reached during the time between the reconnecting and the input of the change orders by the personnel of the operation and maintenance center of the subscriber networks.